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O I Hv n Fe E m f u m EA Y I, BM 7 M A 6 D 2 2 2 N UNITED STATES PATENT OFFICE.

DANIEL M. BISSELL AND FREDERICK H. LITTLEFIELD, OF BOSTON, MASS.

SAFETY ATTACHMENT FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 226,478, dated April 13, 1880.

Application filed January 28, 1880.

To all whom it may concern:

Be it known that we, DANIEL M. BIssELL and FREnERIoK H. LITTLEFIELD, both of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and Improved Safety Attachment for Elevators, of which the following is a specification.

This device is intended to be applied to both passenger and merchandlse elevators; and its object'is to instantly stop the elevator before it has attained any headway in case the rope breaks or a similar accident occurs.

()ur object is to producea mechanism which will accomplish this result and yet be capable of being applied to any ordinary elevator, without altering the shape of either the elevator or the well, at a very small expense, and the improvement is'illustrated in the accompanying drawings, in which- Figure l is an elevation of a portion of an elevator and elevator-well with our device applied. Fig. 2 is a longitudinal vertical section of the same as it appears when the rope has broken. I

Similar letters of reference indicate like parts.

a is the elevator-well, and 1) represents the top of an elevator. c is a cross-bar extending from one to the other of the two standards d d. The cross-bar is firmly secured to the standards, and the standards to the elevator-top. These standards (I d are each made double or provided with slots and cams c e, pivoted therein. The inner ends of these cams are connected, by means of spiral springs ff, with the elevator-top b, and their outer ends are cut into teeth 6 c.

The lifting-rope g is attached to the bar h, which is under the cross-bar c, and is ,bifurcated at both ends, which are bent back in wardly, so as to inclose the pins 6 0 upon the inner ends of the cams.

The operation of the device is as follows: WVhen the elevator is running the rope 9 draws the bar h up under and against the bar or cross-piece c, stretches the springs f f, and draws the cams c c in and away from the walls of the well, as shown in Fig. 1. In case the rope breaks, the springs f f instantly draw down the inner ends of the cams c c and force their teeth 6 0 into the wood-work of the well, thus instantly stopping the elevator and preventing its descent.

teeth would usually be arranged to enter rather than into the elevator-walls direct, as the beam would be stronger. This beam is, of course, set into the walls of the elevator-well flush with the sides, so as not to alter the shape of the well.

The cams may be placed either at the sides or corners, and, as is evident, but one rope is necessary. I

No violent shock is felt in case of the parting of the rope, as the. shape of the cams allows the elevator to stop easily, the cams making a small portion of a rotation while the teeth are entering the wood-work.

We are aware that it is not new to stop a falling elevator by the use of cams operated by mechanism attached to the elevator, such means being shown in Letters, Patent No. 140,190, granted June 24, 1873. In this patent, however, the cams are in pairs and catch into T- shaped rails, which necessitate the building of an elevator with frame-posts made especially for the purpose of fitting over such rails.

In our invention not only great simplicity is accomplished by the use of simpler and cheaper mechanism, but it, being an attachment, not an elevator, can be applied at slight expense to any elevator, and as the cam-teeth catch directly in the walls of the well the shape of the well requires no alteration.

Having thus fully described our invention, wh at we claim, and desire to secure by Letters Patent, is,-

The hereinbefore-described improved safety attachment for elevators, the same consisting of the slotted standards d (I, cross bar 0, hooked bar It, and the semicircular cams c c e e, pivoted in the slot-ted standards and notched at their outer ends, and held by spiral 9 5 springsfat their inner ends, said mechanism being arranged and constructed as above described, and adapted to force the cams directly into the walls of the elevator-well perpendicularly to their surface, for the purpose set forth.

DANIEL M. BISSELL. FREDERICK H. LITTLEFIELD.

'Witnesses:

HENRY W. WILLIAMS, GEORGE V. MALLON.

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